Field of the Invention
The present invention relates to a sheet supporting device configured to support a sheet and more specifically to a sheet supporting device including a sheet remaining amount indicator indicating a remaining amount of the supported sheet.
Description of the Related Art
Hitherto, an electro-photographic image forming apparatus is being widely applied as a copier, a printer, a plotter, a facsimile, a multifunction printer having a plurality of functions of these machines, and others. An image forming apparatus including a sheet supporting (stacking) device capable of stacking a large number of sheets is now common. Japanese Patent Application Laid-open No. 2004-106983 discloses a sheet supporting device including a sheet remaining amount indicator indicating a sheet remaining amount in linkage with a sheet stacking plate within the sheet supporting device so that a user can confirm the sheet remaining amount within the sheet supporting device.
This sheet supporting device includes a main frame body of a sheet cassette and an auxiliary frame body provided slidably within the main frame body and is configured to be able to extend/contract the sheet cassette by sliding the auxiliary frame body with respect to the main frame body corresponding to a size of a sheet to be stored. In the image forming apparatus including the sheet supporting device, a sheet feeding portion is disposed on a rear side of the apparatus body. Therefore, the sheet cassette is provided such that the main frame body is disposed on the rear side of the apparatus body and the auxiliary frame body is disposed drawably on a front side of the apparatus body.
In this sheet supporting device, the sheet remaining amount indicator includes a turning shaft extendible in a front-back direction, i.e., in a longitudinal direction thereof, across the main frame body and the auxiliary frame body, a detector portion provided at an end on the main frame body side of the turning shaft, and an indicator provided at an end on the auxiliary frame body side of the turning shaft. The detector portion is provided so as to project inside in a sheet width direction from the turning shaft and turns the turning shaft along with an elevation of the sheet stacking plate. The indicator includes an arm projecting toward outside widthwise from the turning shaft and an indicator piece movable up and down corresponding a rotation of the arm, and indicates a sheet remaining amount as the indicator piece moves to a level corresponding to a turning angle of the arm at a front surface of the auxiliary frame body when the arm is turned by the turning shaft. That is, the detector portion turns corresponding to the move of the sheet stacking plate, the turning shaft transmits the turn of the detector portion to the arm, and the turning movement of the arm is converted into a vertical movement of the indicator piece and is indicated as a sheet remaining amount. This configuration makes it possible for the user to readily perceive the indication of the sheet remaining amount even in a state in which the auxiliary frame body is drawn out of the main frame body because the turning shaft is extensible.
However, a length of a movable range of the indicator piece depends on a length of the arm in the sheet supporting device disclosed in Japanese Patent Application Laid-open No. 2004-106983. That is, it is necessary to prolong the arm if the movable range of the sheet remaining amount indicator is to be prolonged, and there is a possibility that the size of the sheet supporting device increases in the sheet width direction if the arm is prolonged.